Iraqi medical officials say security forces have cleared a flashpoint bridge in Baghdad of anti-government protesters using stun grenades and tear gas, in clashes that are among the heaviest since the unrest began last month.

Saturday's confrontations at Sinak bridge pushed the demonstrators back to the nearby Khilani square where clashes wounded 35 people.

The officials spoke on condition of anonymity in line with regulations.

Protesters appeared to be regrouping to try forcing their way again across the bridge, which has seen daily clashes with security forces.

The bridge spans the Tigris and gives access to the heavily fortified Green Zone, the seat of government.

Anti-corruption protests and a heavy-handed security response have resulted so far in more than 250 deaths.